The human body
needs copper -
but too much could be dangerous!
Copper was the first metal used by humans 7'000 years ago. It is also
an essential trace element (the third most important after iron and
zinc). The daily need is 1.5 - 3.0 mg/d. It is absorbed in the
intestine, transported to the liver which distributes it to all other
organs. Any excess is excreted into the bile. Copper deficiency leads
to anemia, delayed wound healing und weakness of connective tissue.
In a rare hereditary disease (Wilson's disease
which affects 1/30,000) the liver is unable to excrete any copper
excess. Copper then accumulates in the liver (leading to cirrhosis or
fulminant hepatic failure) and in the brain (leading to neurological or
psychiatric disturbances).
Kayser-Fleischer ring: copper deposition in the iris in Wilson disease
We are interested in
three aspects of copper metabolism:
- Definition of the mechanisms of copper
homeostasis
- Identification of biomarkers of the state of
copper in
an organism
- New diagnostic methods to detect Wilson
disease
Copper homeostasis
Copper is taken up into
cells by specialized
transport proteins. Copper taken up into a cell binds to special
proteins - copper chaperones. Other transport systems are responsible
for the routing of copper to other cellular compartments or to
incorporate it into enzymes dependent on copper. If there is excess
copper, yet other copper transporters pump it out of the cell.
Most of these proteins
involved in copper
metabolism are highly conserved and evolved very early. Thus, similar
proteins can be found in bacteria, plants and animals up to
man. We are interested in studying these molecular mechanisms in two
bacterial model systems, namely Enterococcus hirae and
Lactococcus lactis. More information on this can be found on our lab website.
Biomarkers
There are no established methods to get a sense of the copper status
(deficiency or excess) of any organism. Therefore, we are searching for
such indicators using biomarkers. Biomarkers are proteins
responding to the level of copper in an organism. Using 2D-gels we
analyze the composition of the lining cells of the gut as a function of
copper availability. Using this technique we observe some proteins
which are up- or downregulated.
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